[Determination of methylmercury in urine by direct mercury analyzer].

Objective: To develop asolvent extraction-direct mercury analyzer method for determination of methylmercury in urine. Methods: After the urinehydrolyzesd by hydrobromic acid, methylmercury was extracted by tolueneand reverse-extracted from L-cysteine solution, it was then detectedbydirect mercuryanalyzer. Results: The linear range was 0.2-50.0 µg/L, and the related coefficient was 0.9999. The relative standard deviations (RSD) within the group were 5.04%-6.64%, and the RSD between the group were 5.65%-8.11 %. The average recovery efficiencies were 85.4%-95.5%. The detection limitation was 0.0482 µg/L and the quantification concentrations was 0.1607 µg/L. Conclusion: The method, which has low detection limit, high sensitivity, easy to operate, is stability for the determination of methylmercury in urine.

Adsorption of lead(II) onto PE microplastics as a function of particle size: Influencing factors and adsorption mechanism.

The adsorption of Pb ions, on high-density polyethylene (PE) microplastics (MPs) with the diameter of 48-500 µm, was examined in this study. According to the Langmuir isotherm, MP of the smallest size, 48 µm, had the greatest adsorption capacity of 0.38 µmol g-1. The mechanism of Pb ions adsorption onto PE MPs was chemical adsorption, in particular, hydrogen bonding and surface complexation. Pb adsorption onto PE particles was proceeded at a rapid rate, as predicted by the pseudo-second-order rate model (R2 > 0.99). The PE 48 µm had the maximum adsorption capacity of 0.44 µmol g-1 (or 0.2 mol m-2) at pH 5. While humic acid can operate as a bridging agent, boosting heavy metal adsorption on the surface of PE MPs, fulvic acid has the reverse effect. The findings indicated that PE particles may serve as a carrier of heavy metals in the aquatic environment, posing perceived risks to the environment and public health.

Transformation of copper oxide nanoparticles as affected by ionic strength and its effects on the toxicity and bioaccumulation of copper in zebrafish embryo.

This study aimed to investigate the transformation of copper oxide nanoparticles (CuO NPs) in aquatic environments under different ionic strength and further examine its effects on copper toxicity and bioaccumulation by monitoring the responses and uptake behaviours of zebrafish embryo. Ionic strength (IS) was simulated according to surface water (1.5 mM), groundwater (15 mM), and wastewater (54 mM), representing low-, mid-, and high-IS water, respectively. At the highest exposure of 10 mg CuO/L, zebrafish larvae mortality was increased from 21.3% to 33.3%, when IS decreased from 54 to 1.5 mM. Low-IS solution also caused the highest numbers of delayed hatching embryo (81.3%) and opaque yolk deformation (36.3%). Copper bioaccumulation markedly increased when larvae were exposed to low-IS water (35%) relative to high-IS water (15%). Exposing to low-IS particularly enhanced copper uptake (~15 ng Cu/g inside embryo), facilitating the copper accumulation in the heart of larvae, whereas aggregated CuO NPs (>500 nm) in mid- and high-IS water were blocked from the embryo and found abundantly in the body axis and tail. Results indicate that CuO NPs in low-IS solutions rapidly form the relatively small CuO NP aggregates with a high copper dissolution, which would pose great concern for aquatic organisms.

[Chlamydia psittaci pneumonia complicated with rhabdomyolysis: a case report and literature review].

Objective: To analyze the clinical characteristics and the diagnosis and treatment of Chlamydia psittaci pneumonia complicated with rhabdomyolysis. Methods: We reported a case of Chlamydia psittaci pneumonia complicated with rhabdomyolysis. We did a literature review on the published reports between January 1978 and May 2020 by searching with the key words of "psittacosis" or "Chlamydia psittaci" and "rhabdomyolysis" in the PubMed database (time frame: January 1, 1967 to May 30, 2020). Results: Our patient was a 64-year-old male presenting with high-grade fever, fatigue, myalgia and dyspnea. A computed tomographic scan of the chest revealed bilateral pneumonia, which was further complicated with rhabdomyolysis during disease progression. This prompted the metagenomic next-generation sequencing, revealing the sequences of Chlamydia psittaci in both the bronchoalveolar lavage fluid and blood. Of the 11 cases in the 3 literature reports that we retrieved, 5 had concomitant rhabdomyolysis (two of which did not have complete clinical information), and the other 6 cases had myositis complicated with an elevated level of creatine phosphokinase. This yielded 3 cases with complete clinical information for our analysis. We had further incorporated their information with the single case managed within our study site. Two were males and the other 2 were females. The patients were aged 66, 46, 44 and 64 years, respectively. All cases had fever and 3 had a contact history with live poultry. Two cases had myalgia and progressed rapidly into having respiratory failure, and the other 2 cases did not develop myalgia and improved significantly after a timely treatment. All 4 cases were cured and discharged after treatment with appropriate antibiotics. No adverse outcomes were observed. Conclusions: The prognosis of Chlamydia psittaci pneumonia complicated with rhabdomyolysis was poor in case of a delayed treatment. Early diagnosis would help reduce the mortality.

CoO-3D ordered mesoporous carbon nitride (CoO@mpgCN) composite as peroxymonosulfate activator for the degradation of sulfamethoxazole in water.

A facile impregnation method was used to fabricate a hybrid CoO-3D ordered mesoporous carbon nitride (CoO@mpgCN) catalyst that effectively activated peroxymonosulfate (PMS) for the degradation of pharmaceutical chemical, exemplified by antibiotic sulfamethoxazole (SMX) in aqueous solutions. The CoO@mpgCN/PMS system exhibited high catalytic reactivity and SMX removal efficiency over a wide pH range with an observed rate constant (kobs) of 0.314 min-1. Furthermore, CoO@mpgCN was stable with consistently high degree of SMX degradation without having cobalt dissolution and loss of catalytic activity for at least five consecutive cycles. The significant catalysis performance of CoO@mpgCN was due to its uniformly distributed mesopores, large specific surface area, and high electron transfer ability at the active CoO sites. Both quenching experiments and electron paramagnetic resonance (EPR) analysis verified the yield, in abundance, of highly active species, specifically SO4- and OH from the CoO@mpgCN activation of PMS, primarily. Hence, SMX degradation followed a radical chain reaction mechanism. The result of this study revealed a novel prospective of CoO@mpgCN composite as PMS activator for the remediation of recalcitrant pollutants in water.

Biochar derived from red algae for efficient remediation of 4-nonylphenol from marine sediments.

4-Nonylphenol (4-NP), a phenolic endocrine disruptor chemical (EDC), is known to have high toxicity to aquatic organisms and humans. The remediation of 4-NP-contaminated marine sediments was studied using red algae-based biochar (RAB) thermochemically synthesized from Agardhiella subulata with simple pyrolysis process under different temperatures of 300-900 °C in CO2 atmosphere. The RAB was characterized by XRD, Raman, FTIR spectroscopy, and zeta potential measurements. The calcium in RAB efficiently activated sodium percarbonate (SPC) to generate reactive radicals for the catalytic degradation of 4-NP at pH 9.0. The oxygen-containing functional groups reacted with H2O2, which increased the generation of reactive radicals under alkaline pH condition. Ca2+ ion was the active species responsible for 4-NP degradation. CaO/CaCO3 on RAB surface enhanced direct electron transfer, increased HO production, and 4-NP degradation in marine sediments. Langmuir‒Hinshelwood type kinetics well described the 4-NP degradation process. Remediation of contaminated sediments using RAB could be a sustainable approach toward closed-loop biomass cycling in the degradation of 4-NP contaminants.

[Analysis of 2-level logistic model on influencing factors of suspected occupational diseases].

Objective: To investigate the detection of suspected occupational diseases in the occupational health examination population in Hangzhou, and to establish a two-level logistic model of influencing factors. Methods: In October 2018, the information of physical examinees was collected through the 2015-2017 occupational health examination and reexamination database of Hangzhou Hospital for the Prevention and Treatment of Occupational Disease. MlwiN 2.02 software was used to establish a 2-level logistic model of suspected occupational diseases, with the occupational hazard factors as the level 2 unit and the employees as the level 1 unit. χ(2) test was used to compare the detection rates of suspected occupational diseases with different characteristics. The trend of detection rates of suspected occupational diseases with age and working age were tested by Cochran-Armitage trend test. Results: The morbidity rate of suspected occupational diseases in 2965 workers was 59.6% (1767/2965) , and the rates caused by different occupational hazardous factors were significantly difference (χ(2)=1615.27, P<0.01) , that caused by noises was the highest (98.0%, 1206/1231) , and the next was the dust (87.5%, 70/80) . The rate in male was 61.5% (1532/2492) , and that in female was 49.7% (235/473) , they were significantly difference (χ(2)=22.96, P<0.01) . The rates of suspected occupational diseases increased with the ages (Z=8.77, P<0.01) and working years (Z=3.62, P<0.01) . The multivariate analysis by 2-level logistic model indicated that gender, age and working year were all no significant, instead the level 2 unit random effect was significant (χ(2)=4.77, P<0.05) . Conclusion: Suspected occupational diseases will occur in clusters in occupational hazardous factors. The influence of occupational hazardous factors on suspected occupational diseases was more than that of personal characteristics.

Electrochemical analysis of naproxen in water using poly(l-serine)-modified glassy carbon electrode.

A poly(l-serine)-modified glassy carbon electrode (PLS/GCE) was fabricated by electropolymerization and used to study the detection of naproxen (NPX), a representative non-steroidal anti-inflammatory drug, in phosphate buffer supporting electrolyte at pH 5.0. Results indicated that the PLS/GCE was capable of determination of NPX at a working potential of 0.92 (vs. Ag/AgCl) in voltammetry mode. Experimental factors such as scan rate, accumulation time, solution pH, initial NPX concentration, and interferences were optimized for NPX determination efficiency. The morphology and elemental distribution of the electrode surface were characterized by ESEM, TEM, PSD, XRD, FTIR, TGA, XPS, and zeta potential. NPX oxidation current increased with increasing analyte concentration and scan rate but decreased with increasing pH. Linear sweep voltammetry calibration curve was established in the NPX concentration range of 4.3-65 µM, with detection limit and average recovery of 0.69 µM (n = 3) and 104 ± 2.5%, respectively. PLS/GCE is simple, accurate, reproducible, and easy for operation, therefore would be cost-effective for the determination of NPX.

Loofah-derived activated carbon supported on nickel foam (AC/Ni) electrodes for the electro-sorption of ammonium ion from aqueous solutions.

Activated carbon (AC), prepared from dried loofah sponge, was supported on nickel foam to fabricate AC/Ni electrodes. The characteristics of ammonium electrosorption on AC/Ni electrodes was studied. Results showed that AC prepared in one-step activation (without pre-pyrolysis), i.e., OAC, had relatively low crystallinity, high mesoporosity, and high specific capacitance compared to those made in two-step carbonation followed by activation. Adsorption and desorption density of NH4+ were measured at constant potential of -1.0 V (vs. Hg/HgO) and +0.1 V (vs. Hg/HgO), respectively. Non-faradaic charging contributed to the electrochemical storage and adsorption of ammonium ions on the AC surface with a maximal charge efficiency of 80%, at an applied potential of -1.0 V (vs. Hg/HgO). Multiple-layer adsorption isotherm better described the electrosorption of ammonium ion on OAC/Ni electrodes yielding a maximum adsorption capacity of 6 mg-N g-1, which was comparable with other similar systems. Overall, results clearly demonstrated the effect of synthesis strategy on the capacitive charging behaviors of AC/Ni electrodes and its relationship to NH4+ electrosorption.

The role of fluoroaluminate complexes on the adsorption of fluoride onto hydrous alumina in aqueous solutions.

Activated alumina (AA) has been extensively applied in the defluorination of industrial wastewaters and groundwater. Although the dissolution of AA due to formation of fluoroaluminate complexes (AlFx3-x), especially in acidic condition, has been observed, its role on fluoride uptake by alumina has not been discussed in any previous literature, most of which consider F- as the sole adsorbed species. The present study described the effect of fluoroaluminate complexes on fluoride adsorption onto alumina. Results indicated that fluoroaluminate complexes, major fluoride species at pH < 6, were responsible for total fluoride adsorbed. Free fluoride ions were adsorbed mainly in the alkaline pH region, e.g., pH > 6. The dissolution of AA during defluorination was measured and analyzed by the thermodynamic solubility model. The surface concentration of F- and AlFx3-x were calculated considering electrostatic interactions. Characterization of fluoride-laden AA by XPS revealed that the fraction of surface Al-F species decreased with pH, which suggested the transition of the surface fluorinated species to that of free fluoride ions. The stability constants of four surface complexes, namely, AlOH-FAl2+, AlOH-F2Al+, AlOH2+-F- and AlOH-F-, were 106.88, 105.36, 102.72 and 102.36, respectively. Obviously fluoroaluminate complexes exhibited stronger chemical bonds with the surface hydroxy species than free fluoride.

The adsorption characteristics of fluoride on commercial activated carbon treated with quaternary ammonium salts (Quats).

Commercial activated carbon was treated with six quaternary ammonium salts (Quats), namely, hexyltrimethylammonium (HTMA), octyltrimethylammonium (OTMA), decyltrimethylammonium (DCTMA), dodecyltrimethylammonium (DDTMA), Tetradecyltrimethylammonium (TDTMA), and hexadecyltrimethylammoium (HDTMA) as to enhance the fluoride adsorption capacity. In batch mode experiments, fluoride adsorption onto the Quats-treated activated carbon decreased dramatically with increase in solution pH. Fluoride removal by the Quats-treated activated carbons was closely related to the Quats chain length at less-than critical micelle concentration (CMC). Multi-site adsorption isotherm described fluoride adsorption characteristics well. Results showed that activated carbon treated with DDTMA exhibited the best fluoride adsorption density among all Quats investigated. DDTMA-treated activated carbons exhibited two-fold increase in the fluoride adsorption capacity compared to the untreated activated carbon. Results of regeneration, by alkaline desorption and/or Quats re-loading, showed fluoride-laden activated carbons have high reusability. DDTMA increased the positive surface charge of the activated carbon that enhanced fluoride adsorption. DDTMA-treated activated carbon was promising for fluoride removal from water with much enhanced removal capacity.

The degradation of phthalate esters in marine sediments by persulfate over iron-cerium oxide catalyst.

This study investigated the degradation of phthalate esters (PAEs) in marine sediments by sodium persulfate (Na2S2O8, PS) activated by a series of iron-cerium (Fe-Ce) bimetallic catalysts (FCBCs). The surface structure and chemistry of the FCBCs were characterized by TEM, HRTEM, XRD, FTIR, BET and XPS. Results show successful synthesis of FCBC catalysts. Factors such as PS concentration, Fe to Ce molar ratio, catalyst dosage, and initial pH that might affect PAEs degradation were investigated. Results revealed that PAEs was degraded more effectively over FCBC with a Fe-Ce molar ratio of 1.5:1. Increase in Ce improved the catalytic activity of FCBC due to increase in oxygen storage capacity (OSC). Acidic conditions enhanced PAEs degradation with a maximum degradation of 86% at pH 2 and rate constant (kobs) of 1.5 × 10-1 h-1 when the PS and FCBC concentrations were to 1.0 × 10-5 M and 1.67 g/L, respectively. Di-(2-ethylhexyl) phthalate (DEHP) was a salient marker of PAE contamination in sediments. Dimethyl phthalate (DMP) and diethyl phthalate (DEP) were easier to degrade than DEHP, diisononyl phthalate (DINP), dioctyl phthalate (DnOP) and diisononyl phthalate (DIDP). The synergistic catalytic effect of Fe3+/Fe2+ and Ce4+/Ce3+ redox couples, in addition to electron transfer of oxygen vacancies, activated S2O82- to generate SO4- and HO radicals, which played the major role of PAEs degradation. 5,5-dimethyl-1-pyrroline N-oxide (DMPO) spin trapping EPR studies verified the crucial role of SO4- and HO in the oxidative degradation process. FCBC/PS oxidation exhibited high-performance for the remediation of PAEs-contaminated marine sediments.

Cobalt-impregnated biochar (Co-SCG) for heterogeneous activation of peroxymonosulfate for removal of tetracycline in water.

Cobalt-impregnated spent coffee ground biochar (Co-SCG) was synthesized and applied for tetracycline (TC) removal from water. The results showed that Co-SCG biochar exhibited marked adsorption capacity and catalyst activity. The maximum adsorption capacity of Co-SCG biochar toward TC was 370.37 mg g-1. TC was almost completely degraded in 25 min with a rate constant of 17.78 × 10-2 min-1 under the following optimal condition: TC concentration of 0.2 mM, PMS concentration of 0.6 mM, Co-SCG dosage of 100 mg L-1, and pH of 7.0. Co-SCG was characterized for surface properties by SEM, TEM, HRTEM, and BET. The concentration of 16 PAHs in Co-SCG biochar was studied also. Results demonstrated that Co-SCG was an effective eco-friendly material for the removal of tetracycline from water.

The effect of crystal phase of manganese oxide on the capacitive deionization of simple electrolytes.

MnO2 is a common material for the fabrication and design of capacitive deionization (CDI) devices but there is little information on the role of MnO2 crystal phase on CDI performance. A series of MnO2 (α, ß, γ, and δ phase) were synthesized and fabricated as cathodes for studying the CDI performance as affected by pH in simple batch mode experiments. Our results revealed that the deionization efficiency decreased with increased negative surface charge as a result of the deprotonated surface. Importantly, this correlation was pH independent and the surface heterogeneity due to different MnO2 phase was likely responsible for the different degree of surface ionization and consequently the CDI efficiency. Results of electrochemical impedance spectroscopy analyses further implicated that a highly ionized surface would result in a diffusion layer with a great resistance that conversely inhibited the access of co-ions in the CDI process. This indicated the applied potential was mainly responsible for driving ions transporting through the double layer resistance instead of accommodating them (electrosorption). Based on our results, the surface heterogeneity as a result of different spatially distributed MnO6 octahedral would be accounted for the varying degree of surface ionization and consequently the discrepancy in CDI efficiency among different MnO2 phases.

Preparation of a magnetic reduced-graphene oxide/tea waste composite for high-efficiency sorption of uranium.

The preparation and application of adsorptive materials with low cost and high-efficiency recovery of uranium from nuclear waste is necessary for the development of sustainable, clean energy resources and to avoid nuclear pollution. In this work, the capacity of tea waste and tea waste hybrids as inexpensive sorbents for uranium removal from water solutions was investigated. Composites of graphene oxide (GO) and tea waste (TW) exhibited a promising adsorption performance for uranium from aqueous solutions. The composites GOTW and magnetic rGO/Fe3O4/TW show high adsorption capacities (Qm (TW) = 91.72 mg/g, Qm (GOTW) = 111.61 mg/g and Qm (rGO/Fe3O4/TW) = 104.95 mg/g) and removal rates (~99%) for U(VI). The equilibrium sorption of the adsorbents fitted well to the Langmuir model, and the sorption rate fitted well to a pseudo-second-order kinetic model. The thermodynamic parameters indicated that sorption was spontaneous and favourable. The prepared adsorbents were used for the removal of uranium from real water samples as well. The results revealed that GOTW and rGO/Fe3O4/TW can be used to remediate nuclear industrial effluent as a potential adsorbent.

Electro-sorption of ammonium ion onto nickel foam supported highly microporous activated carbon prepared from agricultural residues (dried Luffa cylindrica).

An electrode made of loofah sponge derived activated carbon supported on nickel foam (AC/Ni) was successfully fabricated and used to remove ammonium ion (NH4+) from aqueous solution. A multilayer adsorption isotherm was used to describe ammonium electro-sorption on AC/Ni electrodes at different temperature, initial NH4+ concentration, and electrical field. The cyclic voltammetry (CV) results suggested that the electrical capacitance of AC/Ni electrodes, with the AC being prepared without preheating (OAC) or with low temperature heating (i.e., 300 AC), were higher than those prepared at high preheating temperature (i.e., 400 AC and 500 AC). Increasing the electro-sorption temperature from 10 to 50 °C decreased the monolayer NH4+ adsorption capacity from 5 to ca. 2-3 mg-N g-1, respectively. Background electrolyte, namely, sodium sulfate, exhibited significant competitive effect on the adsorption of ammonium ion at sodium ion concentration > 10-2 M. The activation energy and heat of adsorption were 9-23.2 kJ mol-1 and -3.7--10.7 kJ mol-1, respectively, indicating a physisorption and exothermic adsorption characteristics. Based on the kinetics and thermodynamics analysis, there was slight increase in the activation energy with elevating preheating temperature, which increased the quantity of micro-pores and surface heterogeneity of the AC materials. Overall, results clearly demonstrated that carbon pyrolysis played a role on the capacitive charging behaviors of electrodes and the efficiency of NH4+ electro-sorption on the AC/Ni electrodes.

Activation of persulfate by CoO nanoparticles loaded on 3D mesoporous carbon nitride (CoO@meso-CN) for the degradation of methylene blue (MB).

A simple and facile synthesis method is developed for the fabrication of CoO loaded ordered mesoporous carbon nitride (CoO@meso-CN) composites, at various CoO loadings, and used, for the first time, to activate persulfate (PS) for methylene blue (MB) degradation. The interfacial interaction between the ultrafine CoO nanoparticles, immobilized by high surface area, regular mesopores, and graphitic nature of the meso-CN support can further enhance the catalytic activation of PS for methylene blue (MB) degradation. Among all catalysts studied, the 5-wt% CoO@meso-CN exhibits the best catalytic performance with a kobs of 0.264 min-1. High initial pH, especially at pH-11, is more beneficial for PS activation. Furthermore, the CoO@meso-CN nanocatalyst is highly stable with a consistently high degree of MB degradation and negligible cobalt leaching for at least 5 consecutive catalytic cycles. Both SO4- and OH are the major reactive species based on results of EPR and quenching experiments. The degradation intermediates of MB are also identified by HPLC/MS/MS and the possible degradation pathway is proposed. Results clearly demonstrate that CoO@meso-CN is a promising green catalyst with enormous potential for the remediation of hazardous chemicals using PS.

A dual TiO2/Ti-stainless steel anode for the degradation of orange G in a coupling photoelectrochemical and photo-electro-Fenton system.

A dual-anode consists of stainless steel and TiO2/Ti electrodes is used to study the kinetics of the degradation of hazardous chemicals exemplified by azo dye orange G (OG) using a coupling photoelectrochemical catalytic and photoelectro-Fenton (PEC/PEF) system. Concurrent generation of hydroxyl radicals on the TiO2/Ti photocatalyst and in-situ generation of Fenton reagents on the stainless steel electrode greatly enhances the performance of the PEC/PEF electrodes over that of the PEC and the PEF alone process. The efficiency of the PEC/PEF process is a function of Fe2+ and H2O2 concentration OH⋅ in the solution bulk, which promotes the oxidative degradation of OG and its byproducts. The mean carbon oxidation state (COS) is estimated to reflect the degree of mineralization. Based on the pseudo first-order kinetics with respect to OH, OG, Fe2+, the corresponding reaction rates is established. UV-Vis spectrometry reveals the presence of four major intermediates, which helps establish the OG degradation pathways.

Photocatalytic degradation of bisphenol A over a ZnFe2O4/TiO2 nanocomposite under visible light.

A ZnFe2O4-TiO2 nanocomposite combining p-type ZnFe2O4 and n-type TiO2 was successfully fabricated. The ZnFe2O4-TiO2 nanocomposite greatly enhanced the bisphenol A (BPA) photodegradation under visible light irradiation at 465 ±â€¯40 nm. Loading TiO2 with 1 wt% of ZnFe2O4 produced high photocurrent and low charge transfer resistance. The photodegradation rate of BPA by ZnFe2O4-TiO2, which was highly dependent on the water chemistry including pH, anions, and humic acid, was 20.8-21.4 times higher than that of commercial TiO2 photocatalysts. Chloride and sulfate ions enhanced BPA photodegradation mostly due to the production of more radical species; whereas nitrate, dihydrogen phosphate, and bicarbonate ions decreased the photodegradation rate of BPA due to the scavenge of hydroxyl radicals. The photoactivity and recyclability of ZnFe2O4-TiO2 in lake water was also assessed. A near complete BPA removal from lake water was observed under visible light irradiation. Furthermore, >90% of photocatalytic activity toward BPA degradation was achieved in 5 cycles of continuous addition of BPA to the lake water. The BPA degradation intermediates were identified by HPLC/MS/MS and possible reaction pathways were proposed. Results clearly demonstrate the excellent visible-light-sensitive photocatalytic degradation of BPA over ZnFe2O4-TiO2 composite which has a great application potential for the decomposition of emerging contaminants in impaired waters.